Related Applications
This application claims priority under 35 USC 119 from GB 9007012.9 filed Mar. 29, 1990 and assigned to EATON CORPORATION, the assignee of this application.
1. Field of the Invention
The present invention relates to vehicular throttle control systems for selectively controlling the supply of fuel to a vehicular internal combustion engine. In particular, the present invention relates to a throttle control system which normally fuels the vehicular engine in accordance with operator demands as indicated by the operator's positioning of the throttle/accelerator pedal but which, in certain modes, is operable to override the operator demands and supply fuel to the engine in a predetermined manner independent of the positioning of the throttle pedal. Such systems are typically associated with automatic/semi-automatic transmission systems having a certain degree of automation to the extent that driver control of the throttle or other fuel feed actuator is overridden by automatic means during gear ratio changes.
More particularly, the present invention relates to fuel control systems having a sender or master control operated by the vehicle operator, a control unit which is typically a microprocessor-based ECU, and a receiver unit which is controlled by the control unit and is effective to position the throttle device, and includes logic means for sensing faults in either the sender or receiver unit and for responding thereto.
It is understood that the term "throttle" and terms of similar import are intended to include various types of throttling devices, fuel injection pumps, fuel injection racks and similar devices which may be selectively controlled to provide variable amounts of fuel and fuel/air mixtures to a controlled vehicular internal combustion engine.
2. Description of the Prior Art
Manual nonsynchronized vehicular change gear transmissions which rely on the vehicle operator having sufficient skill to accelerate or decelerate his engine in unison with his selected gear changes are, of course, well known in the prior art as may be seen by reference to U.S. Pat. Nos. 3,105,395; 4,754,665 and 4,735,109, the disclosures of which are hereby incorporated by reference. Synchronized transmissions and/or transmissions utilizing fluid fly wheels (i.e., torque converters) reduce the necessity of the vehicle operator properly controlling the speed of his engine during gear shifting but tend to be more costly, less fuel efficient and/or less robust than nonsynchronized mechanical transmissions. Automatic and semi-automatic mechanical transmission systems wherein gear shifts are at least partially automatically selected and/or implemented and wherein the fueling of the engine is automatically controlled during a transmission shift are also known in the prior art as may be seen by reference to U.S. Pat. Nos. 4,361,060; 4,648,290 and 4,722,248, the disclosures of which are hereby incorporated by reference.
Typically, the overriding throttle controller utilized in such automatic/semi-automatic transmission systems involves a control unit, typically a microprocessor based ECU, which receives input signals from various sensors including at least one sensor providing a signal indicative of the operator's positioning of a throttle pedal or the like and which sends command output signals to an actuator for adjusting the positioning of the fuel throttling device.
Upon completion of the automated or semi-automated shift operation, the control of the fuel throttling device is returned to the operator whereby the fuel throttling device will be directly controlled by the operator, or controlled by the ECU to directly track the requirements of the operator. Logic for the return of fueling control to the operator is known in the prior art and an example thereof may be seen by reference to U.S. Pat. No. 4,711,141, the disclosure of which is hereby incorporated by reference.
Logic for sensing faulty throttle position sensors and for fault tolerance logic associated therewith, is known in the prior art and examples thereof may be seen by reference to U.S. Pat. Nos. 4,833,614 and 4,922,425, the disclosures of both of which are hereby incorporated by reference.
In vehicular throttle control systems, especially throttle control systems having an override mode of operation, it is important to be able to sense faults in either the master control or sender device, the receiver or actuator device, and/or in a lack of conformity between the sender and the actuator.